Patent US4478665A successfully refreshed from Google Patents.
US4478665A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for manufacturing highly porous, high strength PTFE articles
Assignee: W.L. Gore and Associates Inc
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Filing: 1983-01-21
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Granted: 1984-10-23
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Expires: 2003-01-21
Abstract
Abstract A method for producing a multi-component, porous PTFE article. Components of PTFE containing a liquid lubricant are placed in intimate contact, dried and then stretched in one or more directions. The PTFE components may optionally contain a filler. The resultant product has a virtually uninterrupted structure at the join and possesses very high bond strengths.
Inventors
- 👤 Daniel E. Hubis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:40
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/28; A; A61; A61F; A61F2/00; B; B29; B29C; B29C55/00; B29C55/02; B29C55/023; C08J5/00; C08J5/12; B29K; B29K2027/00; B29K2027/12; B29K2027/18; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
84 words
A process for making a multi-layer article of porous expanded polytetrafluoroethylene comprising: (a) intimately superimposing on top of one another at least two layers of unsintered polytetrafluoroethylene containing a liquid lubricant, at a temperature below the crystalline melt point of polytetrafluoroethylene; (b) removing said lubricant from said multi-layer article; (c) expanding in at least one direction said multi-layer article, from which the lubricant has been removed, at a rate exceeding 10% per second at an elevated temperature below the crystalline melt point of polytetrafluorethylene.
Claim 2
Dependent Claim
84 words
A process for making a multi-layer article of porous expanded polytetrafluoroethylene comprising: (a) intimately superimposing on top of one another at least two layers of unsintered polytetrafluoroethylene containing a liquid lubricant, at a temperature below the crystalline melt point of polytetrafluoroethylene; (b) removing said lubricant from said multi-layer article; (c) expanding in at least one direction said multi-layer article, from which the lubricant has been removed, at a rate exceeding 10% per second at an elevated temperature below the crystalline melt point of polytetrafluorethylene.
Claim 3
Dependent Claim
17 words
The process of claim 1 wherein said contacting is performed in the nip between two calender rolls.
Claim 4
Dependent Claim
17 words
The process of claim 1 wherein said expansion is performed at a rate exceeding 50% per second.
Claim 5
Dependent Claim
17 words
The process of claim 1 wherein said expansion is performed at a rate exceeding 1000% per second.
Claim 6
Dependent Claim
17 words
The process of claim 1 wherein said expansion is performed at a rate exceeding 10,000% per second.
Claim 7
Dependent Claim
10 words
The process of claim 1 wherein said expansion is biaxial.
Claim 8
Dependent Claim
12 words
The process of claim 6 wherein said biaxial expansion is performed simultaneously.
Claim 9
Dependent Claim
10 words
The process of claim 1 wherein said expansion is multi-axial.
Claim 10
Dependent Claim
12 words
The process of claim 8 wherein said multi-axial expansion is performed simultaneously.
Claim 11
Dependent Claim
15 words
The process of claim 1 wherein at least one of said layers contains a filler.
Claim 12
Dependent Claim
11 words
The process of claim 10 wherein said filler is a pigment.
Claim 13
Dependent Claim
12 words
The process of claim 10 wherein said filler is TiO 2 .
Claim 14
Dependent Claim
20 words
The process of claim 12 wherein said filler is TiO 2 having an average particle diameter of about 20 nanometers.
Claim 15
Dependent Claim
11 words
The process of claim 10 wherein said filler is carbon black.
Claim 16
Dependent Claim
11 words
The process of claim 10 wherein said filler is a mica.
Claim 17
Dependent Claim
10 words
The process of claim 10 wherein said filler is asbestos.
Claim 18
Dependent Claim
10 words
The process of claim 10 wherein said filler is silica.
Claim 19
Dependent Claim
10 words
The process of claim 10 wherein said filler is glass.
Claim 20
Dependent Claim
11 words
The process of claim 10 wherein said filler is potassium titinate.
Claim 21
Dependent Claim
12 words
The process of claim 10 wherein said filler is a dielectric fluid.
Claim 22
Dependent Claim
10 words
The process of claim 10 wherein said filler is polysiloxane.
Claim 23
Dependent Claim
28 words
The process of claim 1 wherein said multi-layer article after expansion is heated to a temperature above the crystalline melt point of polytetrafluoroethylene to partially sinter said article.
Claim 24
Dependent Claim
28 words
The process of claim 1 wherein said multi-layer article after expansion is heated to a temperature above the crystalline melt point of polytetrafluoroethylene to fully sinter said article.
Claim 25
Dependent Claim
20 words
The process of claim 22 wherein said article is further stretched after heating above the crystalline melt point of polytetrafluoroethylene.
Claim 26
Dependent Claim
20 words
The process of claim 23 wherein said article is further stretched after heating above the crystalline melt point of polytetrafluoroethylene.
Claim 27
Dependent Claim
13 words
The process of claim 1 in which said layers are extrudates of polytetrafluoroethylene.
Claim 28
Dependent Claim
21 words
The process of claim 1 in which said layers are expanded porous polytetrafluoroethylene layers that have been wetted with liquid lubricant.
Claim 29
Dependent Claim
76 words
A process for making a multi-layer article of porous expanded polytetrafluoroethylene comprising: (a) initially superimposing on top of one another at least two layers of unsintered polytetrafluoroethylene containing a liquid lubricant, at a temperature below the crystalline melt point of polytetrafluoroethylene; (b) stretching said multi-layer article at a temperature below the boiling point of said lubricant; (c) removing said lubricant from said stretched article; (d) expanding said multi-layer article at a rate exceeding 10% per second.
Claim 30
Dependent Claim
76 words
A process for making a multi-layer article of porous expanded polytetrafluoroethylene comprising: (a) initially superimposing on top of one another at least two layers of unsintered polytetrafluoroethylene containing a liquid lubricant, at a temperature below the crystalline melt point of polytetrafluoroethylene; (b) stretching said multi-layer article at a temperature below the boiling point of said lubricant; (c) removing said lubricant from said stretched article; (d) expanding said multi-layer article at a rate exceeding 10% per second.
Claim 31
Dependent Claim
15 words
The process of claim 28 wherein at least one of said layers contains a filler.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-10-23 | 1988-04-23 | 1988-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-23 | 1992-04-23 | 1992-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-23 | 1996-04-23 | 1996-10-23 | $7700.00 | Window Closed / Lapsed |